Exercise as Adjunct Therapy in Cancer
Data from observational studies indicate that both physical activity as well as exercise (ie, structured physical activity) is associated with reductions in the risk of recurrence and cancer mortality after a diagnosis of certain forms of cancer (1,2,3)
Emerging evidence from preclinical studies indicates that physical activity/exercise paradigms regulate intratumoral vascular maturity and perfusion, hypoxia, and metabolism and augments the antitumor immune response
- may enhance response to standard anticancer treatments
- exercise improves efficacy of chemotherapeutic agents - may also improve radiotherapy response
- oxidative stress is present in untreated tumors, and may increase following some treatment modalities
- oxidative stress, along with closely associated tumor hypoxia and acidic microenvironments, contributes to tumor aggressiveness and cancer fatigue - exercise may provide a nonpharmacological therapy of regulating oxidative stress thereby alleviating these factors
- evidence shows that exercise exerts other effects on tumor physiology including alterations in hypoxia, vascular normalization, metabolic reprogramming, and immune cell mobilization (1,2,3)
US guidance states that physical exercise post diagnosis for breast cancer, colon cancer and prostate cancer - is associated with increased survival (4):
- "..A growing body of literature supports an inverse association between greater amounts of physical activity and decreased all-cause and cancer-specific mortality in individuals with a diagnosis of breast, colorectal, or prostate cancer, with risk reductions ranging from 38 to 48 percent. The lack of information about confounding or effect modification by type and completion of treatment reduced the strength of the findings. However, given the statistical significance and effect sizes of the observed associations, the Subcommittee supports recommendations to breast, colorectal, and prostate cancer survivors to increase physical activity. Given the lack of information on physical activity in relation to survival in individuals with cancers other than breast, colorectal, or prostate cancer, no conclusions or recommendations can be made for these cancer survivors. Physical activity should be encouraged to improve survival in individuals diagnosed with breast, prostate, or colorectal cancer.."
The American Society of Clinical Oncology (ASCO) have stated (5):
- Oncology providers should recommend aerobic and resistance exercise during active treatment with curative intent to mitigate side effects of cancer treatment (Type: evidence based, benefits outweigh harms; Evidence quality: moderate to low; Strength of recommendation: strong)
- Note: Exercise interventions during active treatment reduce fatigue; preserve cardiorespiratory fitness, physical functioning, and strength; and in some populations, improve QoL and reduce anxiety and depression. In addition, exercise interventions during treatment have low risk of adverse events. Evidence was not sufficient to recommend for or against exercise during treatment to improve cancer control outcomes (recurrence or survival) or treatment completion rates
- Oncology providers may recommend preoperative exercise for patients undergoing surgery for lung cancer to reduce length of hospital stay and postoperative complications (Type: evidence based, benefits outweigh harms; Evidence quality: low; Strength of recommendation: weak)
Vigorous physical activity (VPA) and mortality (6)
- VPA
- is defined as physical activity at an energy expenditure rate of at least six metabolic equivalents (METs)
- one MET, or metabolic equivalent, is the amount of oxygen consumed while sitting at rest
- thus, an activity classified as 2 METS would be equal to 2 times the amount of oxygen consumed while sitting at rest (1 MET)
- examples of VPAs include running (>5 mph) and swimming
- is a time-efficient way to achieve recommended physical activity levels
- study findings based on:
- prospective study in 71,893 adults [median age (IQR): 62.5 years (55.3, 67.7); 55.9% female] from the UK Biobank cohort with wrist-worn accelerometry
- mean follow-up of 5.9 years
- compared to participants with zero minutes of VPA, the incidence rate ratio among participants with 10 to 30 min/week was approximately one-third for all-cause [0.35 (95% CI: 0.30, 0.42)] and CVD mortality [0.34 (0.26, 0.46)] (6)
- rate was about one-half for 10-30 min/week for CVD [0.58 (0.50, 0.67)] and cancer incidence [0.44 (0.34, 0.56)]
- cancer incidence was 0.38 if VPA of > 60 minutes per week
- regarding minimum dose, about 15 min/week was associated with a 16-18% lower all-cause and cancer mortality risk
A cohort study demonstrated that balanced levels of MPA (moderate physical activity), VPA, and MSA (muscle strengthening activity) combined may be associated with optimal reductions of mortality risk (7)
- higher-than-recommended levels of MPA and VPA may further lower the risk of cancer and all-cause mortality, respectively
Reference:
- Idorn M, Thor Straten P, Exercise and cancer: from "healthy" to "therapeutic"?Cancer Immunol Immunother. 2017 May;66(5):667-671
- Ashkraft KA et al. Exercise as Adjunct Therapy in Cancer. Semin Radiat Oncol. 2019 Jan;29(1):16-24.
- Stout NL et al. A Systematic Review of Exercise Systematic Reviews in the Cancer Literature (2005-2017).PM R. 2017 Sep;9(9S2):S347-S384.
- 2018 Physical Activity Guidelines Advisory Committee. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. US Department of Health and Human Services; 2018.
- Ligibel JA et al. Exercise, Diet, and Weight Management During Cancer Treatment: ASCO Guideline. Journal of Clinical Oncology (May 2022)
- Ahmadi MN et al. Vigorous physical activity, incident heart disease, and cancer: how little is enough?, European Heart Journal, 2022;, ehac572, https://doi.org/10.1093/eurheartj/ehac572
- Lopez-Bueno R, Ahmadi M, Stamatakis E, Yang L, del Pozo Cruz B. Prospective Associations of Different Combinations of Aerobic and Muscle-Strengthening Activity With All-Cause, Cardiovascular, and Cancer Mortality. JAMA Intern Med. Published online August 07, 2023. doi:10.1001/jamainternmed.2023.3093